Course detail

# Electrical Machines

FEKT-BESBAcad. year: 2016/2017

The basic laws and equations used in the theory of electrical machines. Magnetic circuits of electrical machines. The basic voltage equations, equivalent circuit diagrams, phasor diagrams, the basic electrical connections of electrical machines. Energy and power flow diagrams, losses and efficiency. Torque equation. Electrical machines' performance. Nonsymmetrical loading. Influence of higher harmonics. Basic characteristics of electrical machines.

Supervisor

Learning outcomes of the course unit

Subject graduate should have been able:

- describe main parts of electric machines,

- know classes of insulation and electrical machines costruction,

- describe construction of transformer,

- explain transformer losses,

- understand and explain single and multiphase transformer operation,

- calculate parameters of transformer equivalent circuit from no-load and short – circuit tests,

- draw and explain phasor diagrams of transformer at no load, at short circuit and generally loaded.

- transformer winding connection and phasor diagram for different hour angle,

- explain and calculate transformer voltage regulation,

- describe and explain construction and principle of operation of induction machine with wound rotor and with squirrel cage,

- describe revolving magnetic field generation,

- define basic kinds of AC machine windings,

- sketch curve of magnetic field of AC winding distributed in more slots,

- draw equivalent induction machine circuit diagram, derive torque equation and draw torque - speed characteristic ,

- describe connection of induction motor into public utility network and speed control,

- describe construction and principle of operation of single phase induction motor,

- describe principle operation and construction of nonsalient synchronous machine,

- draw simplified circuit diagram, derive torque equation and draw phasor diagram,

- explain synchronous generator operation with isolated load and with public utility network, use phasor diagram for explanation,

- explain synchronous compensator principle of operation,

- describe DC machine construction and principle of operation,

- describe basic types of DC machine windings,

- derive torque and induced voltage equations,

- explain properties of DC motors and generators,

- describe construction and explain principle of operation of AC single phase commutator machines.

Prerequisites

Student should have been able to:

-explain and define basic terms magnetic field, electric field, magnetic field, circuits with lumped and distributed parameters,

- solve DC, AC and magnetic circuits,

- solve three phase AC circuits,

- define the terms work and energy,

- describe and explain basic properties soft and hard magnetic materials.

Co-requisites

Not applicable.

Recommended optional programme components

Not applicable.

Recommended or required reading

Fitzgerald,Kingsley,Kusko::Electric Machinery,McGraw-Hill

O'Kelly:Performance and Control of Electrical Machines,McGraw-Hill

Měřička,Haňka,Voženílek.::Elektrické stroje,ČVUT Praha

Planned learning activities and teaching methods

Teaching methods depend on the type of course unit as specified in the article 7 of BUT Rules for Studies and Examinations.

Assesment methods and criteria linked to learning outcomes

Control tests - 20 points

Laboratory and computer exercises - 15 points

Final Exam - 65 points

Language of instruction

Czech

Work placements

Not applicable.

Course curriculum

1. Basic laws of electromagnetism related to electrical machines.

2. Principle of electromechanical energy conversion.

3. Transformers. Ideal transformer, actual transformer, basic equations.

4. Principle of operation and construction of power transformers.

5. Three-phase transformers, winding connection, parallel operation.

6. Magnetic circuit and winding of electrical machines.Principle of operation of induction machine, generation of revolving magnetic field.

7. Equivalent circuit diagram, fundamental equations and torque characteristics.

8. Starting of induction machines speed control.

9. Single-phase induction machine. Three-phase induction machine in single-phase mains. The higher harmonics influence.

10. Synchronous machine. Principle of operation and construction.

11. Theory of nonsalient machine. Torque characteristic, synchronous machine with individual load and parallel operation.

12. DC machines. Principle of operation and construction, fundamental equations.

13. DC machines steady -state performance.

Aims

To acquaint the students with the principle of operation and performance of transformers, induction machines, DC machines and synchronous machines. The theoretical knowledge are proved in laboratory excerscises

Specification of controlled education, way of implementation and compensation for absences

The content and forms of instruction in the evaluated course are specified by a regulation issued by the lecturer responsible for the course and updated for every academic year.

#### Type of course unit

Laboratory exercise

26 hours, compulsory

Teacher / Lecturer